CVE-2018-10084 in CMS Made Simple
Summary
by MITRE
CMS Made Simple (CMSMS) through 2.2.6 contains a privilege escalation vulnerability from ordinary user to admin user by arranging for the eff_uid value within $_COOKIE[$this->_loginkey] to equal 1, because an SHA-1 cryptographic protection mechanism can be bypassed.
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Analysis
by VulDB Data Team • 01/24/2020
The vulnerability identified as CVE-2018-10084 affects CMS Made Simple versions up to 2.2.6 and represents a critical privilege escalation flaw that allows ordinary users to gain administrative privileges. This vulnerability stems from a fundamental weakness in the authentication and session management mechanisms of the content management system, specifically targeting how user permissions are validated during the login process. The flaw enables attackers to manipulate cookie values to assume administrative roles without proper authentication, creating a severe security risk for organizations relying on this platform for their web presence.
The technical root cause of this vulnerability lies in the improper implementation of cryptographic protection mechanisms within the CMSMS authentication system. The system relies on an SHA-1 hash stored in the $_COOKIE[$this->_loginkey] variable to validate user sessions, but this protection can be bypassed through careful manipulation of the eff_uid parameter. When an attacker can control the eff_uid value to equal 1, they effectively assume the highest administrative privileges within the system, as user ID 1 is typically reserved for the primary administrator account. This bypass occurs because the SHA-1 implementation lacks proper cryptographic strength and validation checks, allowing attackers to craft malicious cookie values that pass the authentication verification process. The vulnerability aligns with CWE-310, which addresses cryptographic weaknesses, and specifically demonstrates poor implementation of cryptographic key management and hash validation.
The operational impact of this privilege escalation vulnerability is devastating for affected organizations, as it provides attackers with complete control over the CMSMS installation. Once an attacker successfully exploits this vulnerability, they can modify or delete content, install malicious code, access sensitive data, manipulate user accounts, and potentially use the compromised system as a launching point for further attacks within the network. The vulnerability's exploitation does not require elevated privileges or complex attack vectors, making it particularly dangerous as it can be exploited by anyone who can access the CMSMS platform. From an attacker's perspective, this vulnerability maps directly to ATT&CK technique T1078 which covers valid accounts and privilege escalation through legitimate credentials, and T1548.001 which addresses abuse of sudo privileges through session hijacking.
Organizations affected by this vulnerability should immediately implement mitigations including updating to CMSMS version 2.2.7 or later, where the cryptographic protection mechanism has been properly strengthened. Additionally, administrators should consider implementing additional security controls such as cookie security flags, enhanced session management, and regular monitoring of authentication logs for suspicious activity. The fix addresses the core cryptographic weakness by strengthening the SHA-1 implementation and adding proper validation checks to prevent manipulation of the eff_uid parameter. Security teams should also conduct comprehensive audits of their CMSMS installations to ensure no unauthorized administrative accounts exist and consider implementing network segmentation to limit the potential impact of such attacks. The vulnerability serves as a reminder of the critical importance of proper cryptographic implementation and the dangers of relying on weak hash functions for security purposes.